The “Project Portal” venture assigned to Toyota Motor Corp.’s North American research team was so hush-hush that even suppliers on the project were kept in the dark.

Since September, a tiny cadre of specialists has toiled at a secret technical center in southeast Michigan and then at Toyota’s test track in the desert outside Phoenix to build and refine technology that could transform more than 100 years of trucking technology used to move goods globally.

The experiment — powering an 80,000-pound Class 8 truck-and-trailer combo using Toyota’s cutting-edge clean-tech hydrogen fuel cell system — was successful enough to warrant a second phase. The company is now live-testing a short-haul, zero-emission drayage truck shuttling shipping containers between the ports of Los Angeles and Long Beach and various freight depots up to 70 miles away.

“This has been somewhat of a skunkworks project even within Toyota,” said Sheldon Brown, an engineer who is part of the team.

If the prototype truck proves commercially viable, Toyota could become the first major automaker to enter the fuel cell market for Class 8 vehicles, perhaps through its Hino Trucks unit or by marketing its proprietary powertrains to truck manufacturers nationwide.

The company has plenty of incentives to investigate fuel cells.

The technology produces electricity through a fuel cell stack composed of hundreds of individual cells. The hydrogen is stripped of its electrons, and the resulting electricity directly powers the electric drive motor.

The powertrains don’t produce tailpipe emissions, making the vehicles an attractive solution for an industry notorious for being an egregious polluter. In California, heavy-duty vehicles — including big rigs, buses, delivery trucks and port-based drayage vehicles — account for more than 30 percent of the state’s smog-causing nitrogen oxide, or NOx, emissions and 7 percent of the state’s global warming emissions, according to a study by the Union of Concerned Scientists.

Project Portal Toyota fuel cell truck. (Photo: Toyota)

The fuel cell stacks onboard are smaller and lighter than the massive storage batteries used for a plug-in electric truck, freeing up space for freight. Refueling takes little time. With fewer moving parts, maintenance and repair costs can be lower than for conventional diesel trucks.

Consequently, fuel cell electric trucks should be relatively cost-efficient to operate and competitive with diesel vehicles, said Takehito Yokoo, senior executive engineer for advanced fuel cell development at Toyota North America’s research and development center in Torrance, Calif.

And Toyota fits the mold of an effective first-mover.

“We have more confidence in someone like Toyota doing it than in a new player being successful,” said Lisa Jerram, smart transportation systems analyst with Navigant Research.

But success is far from guaranteed, industry analysts say.

Getting a heavy truck powered by a fuel cell into commercial production “is a long-term play” for Toyota, Jerram said. Besides, there’s “probably not a good case for fuel cell trucks being successful across the U.S.,” she said.

Navigant, however, does see potential for the technology to gain traction in California, Japan and Western Europe.

Such zero-emission vehicles have an advantage in markets where clean-air goals are a major economic driver. The Toyota North America team said it decided to focus on a heavy rig in part because the vehicle could best demonstrate the fuel cell technology while contributing to cleaner air in heavily polluted Southern California.

But for high-performance working vehicles such as commercial trucks, “the technology is challenging,” transportation and energy analysts with IHS Markit told Trucks.com.

Yokoo and others working on Toyota’s truck project don’t disagree. The truck trial is ongoing and designed to address similar concerns about the viability of fuel cells, said Brown, a vehicle integration specialist and executive project manager for Toyota’s fuel cell truck program.

“We still need to understand and demonstrate durability and real-world fuel efficiency,” he said. “It is still too early to discuss a longer-term strategy.”

For now, the team is focusing on trying to build an economic case for fuel cell systems in heavy commercial trucks. Project Portal also hopes to demonstrate that the technology can be adapted to a wide spectrum of transportation uses, Yokoo said.

That’s why Toyota’s truck experiment is so ambitious. The company could have been more cautious — taking its existing compact Mirai fuel cell passenger sedan and scaling it first to a midsize car.

2017 Toyota Mirai fuel cell sedan. (Photo: Toyota)

But “if we can show that the technology applies to the largest trucks, then it will be much easier to show that it can be applied in scale to smaller trucks and bigger cars” as well, Yokoo told Trucks.com.

What Toyota did do was develop a fuel cell version of its popular Tundra pickup truck. Dubbed the Hydra, the prototype pickup was used in Japan as a test bed for developing the control systems used in the Class 8 truck. There’s no intent right now to go into commercial development of a fuel cell pickup, Brown said, but the Hydra, unveiled alongside the heavy-duty fuel cell truck Wednesday, shows that it could be done.

As with the Hydra, many components in Toyota’s fuel cell truck were lifted directly from the Mirai, which Toyota introduced into the U.S., Japanese and European markets last year. Although the sedan isn’t particularly powerful, just two of its fuel cell stacks can sufficiently power its big-rig cousin — a truck that in its diesel iteration would require a 400- to 600-horsepower engine.

The fuel cell truck, however, does rely on a much larger and more powerful electric motor than the Mirai.

Toyota’s initial test truck is a Kenworth T660 chassis. The standard sleeper compartment has morphed into a custom aluminum shell housing a quartet of high-pressure hydrogen tanks and a pair of 6-kilowatt-hour lithium-ion batteries. Although Toyota is keeping mum on the battery manufacturer’s identity, the company’s longtime lithium battery supplier — Panasonic — is the most likely candidate.

The fuel cell system also features a pair of Mirai fuel cell stacks with related cooling, power and control systems as well as two customized electric motors, all tweaked as necessary to handle the demands of a heavy-duty truck.

The fuel cell powers a motor that produces more than 670 horsepower and 1,327 pound feet of torque, roughly the same as the new Cummins X15 Efficiency Series diesel engine. It is capable of both propelling the nearly 11-ton tractor and a loaded trailer at speeds of up to 65 mph and of handling a steep 12 percent grade (a rise of about 40 feet over the length of a football field), Brown said. Because all of the electric motor’s formidable torque is available instantly, Toyota’s prototype truck can handily out-accelerate comparably powered diesels.

Project Portal launched nearly two years ago in Toyota’s North America division and enjoys endorsements, funding and support personnel from throughout the company, Yokoo said.

Only Yokoo, Brown and fellow engineer Giorgio Zoia are permanently attached to the effort. External suppliers help with vehicle integration and components such as custom motors.

The prototype truck entered development roughly a year ago. Fabrication began in September, and the finished truck arrived in Arizona for its initial test run in early February.

Real-world testing in Southern California is slated to begin in June after track testing and system fine-tuning is completed in Arizona. It will be conducted out of Toyota’s Port of Long Beach facility and within the adjacent Port of Los Angeles in conjunction with one or more of the two ports’ freight haulers. The goal is for the truck, laden with cargo, to make regular round trips between the port and warehouse facilities up to 70 miles away, Brown said.

For now, the 40 kilograms of compressed hydrogen that fit inside the truck’s carbon-wound plastic fuel tanks can push the truck and a loaded 60,000-pound trailer at least 150 miles and a 60-percent load of 36,000 pounds about 240 miles. Yokoo is confident that range will improve as the truck’s operating system is fine-tuned.

Setting an initial 70-mile operating radius for the port test allows the truck to return to the port facility for refueling. Toyota will park a hydrogen tanker at the port for refueling; permanent fueling stations would need to be built if the truck is put into production. Toyota is targeting a fueling time of 30 to 40 minutes, but is still fine-tuning the system.

“It’s important that we make it similar to the current diesel refueling experience,” Brown said.

If California’s hydrogen fueling infrastructure continues to grow and fuel cell trucks are no longer tethered to a specific base station for fueling, the travel range will increase, he said.

In a short test spin as a passenger on Toyota’s test track near Wittman, Ariz., Trucks.com found the prototype to be stunningly quick and remarkably quiet.

Without a trailer, the tractor weighs in at just a few pounds less than a comparable diesel rig. It uses the same suspension and delivers the same ride quality. But there’s no diesel rattle or engine vibration to add to the bumps from the road. Nor is there any fuel odor or engine noise, just a slight whine from the single-speed transmission and the occasional hum of the electric air compressor used for the brake system.

In the Trucks.com ride, test driver Jose Gonzalez slowed the tractor to a sedate 25 mph and then floored the accelerator pedal. The nose of the truck lifted and the G-force pressed driver and passenger back into their seats as the truck silently gathered speed. A mere 6.3 seconds had elapsed when Gonzales announced the speedometer read 55 mph.

While not particularly fast for a modern passenger car, it is blazing for a 21,970-pound tractor.

So far, the only other company to propose hydrogen fuel cells for heavy trucks is Salt Lake City start-up Nikola Motors. In December, the company unveiled a nonfunctional prototype of a long-haul Class 8 fuel cell truck. Other companies, including Tesla Inc. and Daimler Trucks, are working on battery-electric trucks.

Construction on a manufacturing and research and development center will take four to five years, according to Nikola. The first working prototype won’t be ready until 2019.

By then, Toyota could be readying a retail model of its own fuel cell truck — as long as it stands up to existing fossil fuel rivals, said Craig Scott, senior manager for advanced business development at Toyota North America.

“We have to have a truck that’s just as good as a diesel truck,” he said, “with the same performance specifications as the [diesel] competition.”